Generally, such a device usually includes:
means for monitoring upon a flight of the aircraft, automatically and repeatedly, a plurality of data of the aircraft so as to be able to detect a low energy situation, for which conditions relative to a low energy are met; and
means for automatically activating in the case where a low energy situation is detected, a protection function involving automatically engaging an autothrottle autothrust (“ATHR”) and automatically controlling the engines of the aircraft so as to supply a maximum thrust.
The protection function is defined in guiding and flight control calculators for the aircraft, and thus generates, in all cases where the aircraft is in a low energy situation, an automatic increase of the thrust so as to achieve the maximum engine thrust, and this whatever regardless of the initial position of the throttles of the aircraft.
From documents FR-2 890 645 and WO-2007/031634, an energy protection device is known for an airplane being provided with at least one engine arranged on each one of its wings and with at least one additional engine. Such a protection device has a broad domain of use, wherein the safety of the airplane is maintained. To this end, it comprises means for inhibiting the protection function, but inhibiting such a function only when all the engines being arranged on one single same wing of the airplane are simultaneously defective, such a situation making critical the dissymmetry created for the lateral control of the airplane. This allows the number of inhibition cases to be considerably reduced. Consequently, such a protection device has a much broader domain of use than previous conventional devices, in particular in the case of one single engine becoming defective or in the case of two engines becoming defective, being arranged on different wings.
When the conditions for triggering a previously activated protection function are no longer met, the autothrottle remains engaged, the maximum thrust is still applied to the engines, and an appropriate message is displayed on a flight mode annunciator of the aircraft.
The protection function could, indeed, be disengaged thru disengaging the autothrottle, requiring a manual action from the pilot. More precisely, in order to disengage the autothrottle, the pilot should act on a dedicated disconnection means, or on the throttles so as to bring them in the idling position, or even on a controlling means relative to the autothrottle on a display of the Flight Control Unit (“FCU”) type.
Consequently, current airplanes exhibit the following restriction. In order to get out of the above mentioned protection mode, pilots have to disconnect manually the autothrottle as a result of the protection function being triggered and this even if the autothrottle was engaged before this protection function was triggered, in order to omit maintaining the blocked engine thrust at the maximum thrust of the Take Off, Go Around “TOGA” type. The crew have afterwards to re-engage the autothrottle for continuing the flight, if the autothrottle is used for the remainder of the flight. So, the crew must sometimes carry out various successive actions so as to return back to a situation being compatible with the remainder of the flight. The crew's workload is thus significant in such a situation.
The present invention aims at solving these drawbacks. It relates to an energy protection method for an aircraft provided with at least one engine and one autothrottle allowing for automatically managing going out of a protection function.